Question: Simplify the following expression: $y = \dfrac{p^2 - p - 42}{p - 7} $
Answer: First factor the polynomial in the numerator. $ p^2 - p - 42 = (p - 7)(p + 6) $ So we can rewrite the expression as: $y = \dfrac{(p - 7)(p + 6)}{p - 7} $ We can divide the numerator and denominator by $(p - 7)$ on condition that $p \neq 7$ Therefore $y = p + 6; p \neq 7$